My Toshiba A75-S209 acted as if it had a short and would switch over to 
battery power every few minutes.  I would jiggle the cord and it wold go 
back to AC power.  I called toshiba and they said that I wold have to send 
it in, and they wold have to replace the power jack and that it would not be 
returned for 3 weeks.  The cost wold be around $200 including labor. 
Naturally, I said Bullshit.  After a little research I found that this is a 
common problem with toshiba users.  Here is the problem and the fix.

Take the computer apart (I would recomend a friend who works in your company 
IT depatment.)  If you dont have one, check with friends in larger companies 
that have an IT department.   These guys always like a few extra bucks.  I 
took mine to one of these guys and he took it apart (Believe me, if you dont 
work on laptops on a regular basis you will never figure out how to 
dissasemble one of these without getting pissed off and breaking somethin) 
Once it is dissembled, tell him to check the center soldered point on the 
power jack which is attached to the motherboard. The factory solder job 
sucks and is the problem not allowing a secured connection.  Have him remove 
the existing solder and redo it.

While the computer is apart, make sure he uses compressed air and blows out 
the entire computer, fans and vents.  Chances are by now you have been 
having problems with your computer heating up and shutting down.  This is a 
real problem with Toshibas if they get any dust buildup whatsoever.

This entire procedure took him 20 minutes and I was up and running.  I asked 
him what I owed, and he said it wasnt a big deal and refused to take my 
money.  I sent him a thank you card with $50 cash anyway with a note 
thanking him and explaining that it would have cost be around $200 dollars 
and the inconveinance of dealing with Toshibas crap.  This was well worth 
it.

This has been 2 weeks ago and I leave my computer running 24 hours a day.  I 
have not had a single power problem or overheating problem since.

I hope this helps everyone.

Thanks
Robert